10.4 Iron Metabolism Flashcards
How much of the body’s iron is stored in RBCs?
Just over 50%
How much iron do we lose in a day? How much do we have in total?
- We lose 1-2mg/day
- Which is not very much, when you consider that we have 3-4g total
Which protein transports iron around in the blood?
Transferrin
Where is iron mainly transported to once in the blood?
- Bone marrow (for erythropoiesis)
- Liver
- Other tissue
Why is a large amount of iron either in macrophages or in the spleen?
- Being recycled
- Will be transported elsewhere eventually by transferrin
What are the main dietary sources of iron? Which is better absorbed?
- Red meat
- Vegetables (such as brocolli)
- Iron from meat is better absorbed due to pH
Which iron ion is bound in haemoglobin?
Fe2+
How does the DMT1 transport protein help us absorb plant-based iron?
It reduces Fe3+ into Fe2+
Which transport protein enables iron to move from enterocyte into blood?
Ferroportin
What happens to iron as it is taken up by transferrin?
It is oxidied back into Fe3+
How does hepcidin decrease iron transport?
It degrades ferroportin
Ferritin vs transferrin
Ferritin is a warehouse that stores iron. When combined with transferring, it can move iron around the body.
How can an inflammatory response mislead us regarding ferritin levels?
Inflammation causes liver to produce more ferritin; this is indicative of inflammation, not of higher iron levels.
Hepcidin is also upregulated during inflammation, so any iron that is actually present is difficult to use.
Hepcidin blocks ferroportin, which can prevent iron transport from exiting…
- Macrophages
- Hepatocytes
- Enterocytes
How does the body change iron absorption during hypoxia? Why?
- Wants to make more RBCs
- Increased DMT1, decreases hepcidin
